In various applications involving chemical process engineering, water treatment, sewerage treatment, mineral separation and the like, it is desirable to dissolve gases such as oxygen, nitrogen, carbon dioxide, sulfur dioxide, air and admixtures thereof into a fluid stream within a pipeline or pipe outlet. Numerous techniques involving injectors and other devices have been developed for this purpose. However, these suffer various disadvantages. For example, most known injectors produce excessively large oxygen bubbles within the fluid stream because of the tendency for the bubbles simply to expand adjacent the injection nozzles. Larger bubbles are not readily dissolved due to the relative decrease in total surface area for a given volume and so diminish the efficiency of the process.
Another disadvantage of known oxygen injection and dissolution devices is that they are prone to rapid wear, particularly in applications involving abrasive slurries or corrosive fluids. This results in excessive downtime and increased expense for maintenance and repair operations. Some known injectors are also prone to clogging and are generally unserviceable without specialized equipment and expertise. In accordance with the present invention, at least some of these disadvantages of the prior art are overcome or substantially ameliorated.